BCM Community
Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Craig R on November 11, 2023, 05:43:59 PM
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Are there any options for replacing the OE MC5c Radiators to achieve more efficient cooling after repowering from 6V71N to 6V71T or 6V71TA (with larger injectors)?
Could the tanks for the radiators out of an MC9 be soldered up with a core that is five inches shorter than MC9 OE and installed in the place of the OE MC5c radiators with limited remodeling of surrounding structures?
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When I had Atlas Radiator in Santa Fe Springs CA make a new core for me, they had to first check that my tanks had standard flanges to match the new core's flanges. Apparently there are some older radiators with weird hole spacings for their tanks' bolts! Mine was standard, so they made a new high-performance 6-row core with more tubes, with dimpled tubes and with 12 fins per inch. I also sealed up the shroud to ensure no air could leak in anywhere, made a 3"-wide duct for the fan, had Multi-Wing make a 9-blade high-efficiency fan with adjustable blades, and had QCC make a new Webster fan motor. I now have no more overheating, but that's also after having the engine completely rebuilt...
John
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I added a 3rd radiator on the passenger side engine door. I took the hot antifreeze lines out of the back of the engine that went to the passenger heater core and turned it around to the 3rd radiator...
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Would one get the same benefit by rerouting outside air thru the heater core and sealing up the ducting to the interior of the coach ?
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From where does the squirrel-cage fan of the OE heater core draw air?
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From where does the squirrel-cage fan of the OE heater core draw air?
Craig -
From memory, I think it's 80% from the interior ducting, and 20% fresh air from the side vents in the billboard area above the condenser on the driver's side and above the battery box on the passenger side.
As for improved cooling, MC-9s and later models that came with the optional 8V92TA engine had thicker radiator cores, larger squirrel cage blowers, a smaller blower driven pulley, rubber "funnels" to direct radiator air into the blowers, and a larger opening in the blower deck below the blowers for increased air flow.
It's also very important that all around the radiators is sealed properly, including the access door seals, as well as the blower compartment door seal. In addition, if currently equipped, removing a mudflap hanging off the back bumper and moving it up to directly behind the rear axle will also create more air flow thru the engine compartment while at speed - something that GMC did with their highway model coaches starting way back in 1953! It works!
FWIW & HTH. . . ;)
RJ